How much does boreing throttle bodies usually cost? What's the max you can bore it out to?

Say a have a 60mm TB, what's the max that it can be bored?

 

dunno how much it costs but i did mines by myself....felt a small gain but its well worth it if you just do it yourself....if a shop does it, it will be way too much. just letting u know

 

you can bore it out yourself but the best way is to get it done and with a new matching plate to go with it.

 

How do you DIY? Are there any how to's? Any would be appreciated.

 

boring a throttle body requires a new butterfly plate, so doing it yourself will be hard to acomplish. I believe the biggest you can get a stock 60mm is to 64mm anything bigger than that and you need to get a custom jobber.
RPM service makes them up to 70mm I believe. They can be bought from JDMhondaparts.com and Ericks racing I believe the cost is around $350 - $400 If all you want is your stock throttle body bored to 64mm RC engineering and JG engine dynamics do it for roughly around $150 - $200

 

Also something to consider is that a bigger TB will sometimes hurt performance, like if it is on a stock b16 intake manifold. And when you bore it is wise to change butterflies out for a larger unit.

Since I am using the stock b16 i.m., I plan on taper boring the tb to 62mm. I know I probably will not see any hp gains, but throttle response should improve a bit. To do it yourself you can get a honing tool, from any tool shop. Attach to a drill and then bore out. However, I'm not sure where you can buy larger butterflies.